Access openings, such as entranceways, doorways, hallways, and areas above countertops are often secured by overhead (vertically traveling) closures.
Rolling steel doors, also referred to as overhead coiling closures, are metal slatted doors which move in a generally vertical path, coiling above the opening as the door is opened. Because rolling steel doors have many fewer parts than sectional doors with less risk for damage and inoperability, they often make a better solution for facilities that cannot afford opening downtime.
Rolling grilles also coil above the opening and provide access control and off hour security on interior and exterior openings, but unlike rolling steel doors simultaneously permit visual access of separated spaces. Grilles prevent unauthorized access and discourage forced entry at building exterior openings, storefronts or areas within buildings, such as pharmacies or parts counters. Used behind plate glass storefronts, they are a deterrent to smash-and-grab crime.
Rolling counter fire doors, also referred to as fire shutters, coil above the opening and are used to secure openings above counters and other similar finished openings on interior and exterior walls. When the compact components of counter fire doors are desired, these units can fully close to the floor.
All of the aforementioned overhead coiling door designs travel within a pair of tracks positioned on either side of the opening. Usually rollers are not utilized. Because there are no rollers extending from the sides of the curtain, the curtain can have a tendency to move off center as it is being raised or lowered. Off center operation increases the likelihood that operative movement will not be smooth, and in extreme circumstances jamming can occur.
Accordingly, there is still a continuing need for improved curtain centering designs. The present invention fulfills this need and further provides related advantages.